Comparison of two formulas for calculating intraocular lens in patients with angle-closure glaucoma

This study compares the accuracy of SRK/T and Barrett Universal II intraocular lens (IOL) measurement formulas for cataract phacoemulsification combined with intraocular lens implantation in angle-closure glaucoma (ACG) patients. Prospective serial case studies were conducted. A total of 146 patients (146 eyes) with ACG complicated with cataract who underwent cataract surgery with atrial angle closure ≤180° were observed. All the patients were divided into 2 groups according to different intraocular lens calculation formula, with 73 cases in each group (73 eyes). SRK/T intraocular lens calculation formula was used in group A, and Barrett intraocular lens calculation formula was used in group B. The visual acuity, the best corrected visual acuity, intraocular pressure and central anterior chamber depth were significantly improved in 146 eyes 3 months after operation, and the differences were statistically significant. There was statistically significant difference in postoperative spherical equivalent (SE) between the 2 groups (t = 2.147, P = .033), and there was statistically significant difference in preoperative expected refraction between group A and postoperative SE (t = 4.221, P < .001). There was no significant difference between preoperative expected diopter and postoperative SE in group B (t = 1.857, P = .065). The difference in absolute predicted error between the 2 groups was statistically significant (t = 4.929, P < .001). Axis length was negatively correlated with SRK/T formula and Barrett Universal II formula absolute refractive error value (ME) (group A: r = -0.740, P < .001; group B: r = -0.532, P < .001), there was A significant negative correlation between absolute refractive error value and anterior chamber depth in both groups (group A: r = -0.382, P = .001; group B: r = -0.358, P = .002). The cataract phacoemulsification combined with intraocular lens implantation is safe and effective for ACG patients with cataract. For such patients, the Barrett Universal II intraocular lens measurement formula may be more accurate after surgery.